Anger drives independents, the non-affiliated swing voters to the polls. We've seen that anger manifest itself in 1994, 2006, 2010 and 2018. Anger for different reasons and about different things. Those were all wave elections which changed control of the House of Representatives. The one thing all four wave elections have in common is independents, the non-affiliated were angry at the party in power for many varied reasons.

When not angry, independents tend to side with the party in power. Things and life are going fairly good, so they'll stay with whoever, whichever party is in power.

Trump, independents dislike of him in my opinion is the glue that has kept a slight majority of independents siding with the Democrats so far in Biden's first term. Which I think we can see with the numbers below.

Independents on Biden’s overall job performance as of 29 Jun 2021 54% approval/42% disapproval.
On the economy 47% approval/ 45% disapproval (2)
On immigration 38% approve/54% disapprove (4)
Foreign policy 46% approve/44% disapprove (8)
Climate change 43% approve/40% disapprove (3)
Education 38% approve/40% disapprove (6)
Healthcare 50% approve/36% disapprove (1)
Civil rights 42% approve/40% disapprove (5)
Crime 36% approve/46% disapprove (7)

Nothing will add up to 100% because of the Don't know/no opinion answers. The number in parentheses are the issues rank in importance to independents. Looking at those numbers, one has to wonder how Biden’s overall job performance among independents is higher than his performance on any one issue? That is probably the Trump factor. The dislike of Trump factor.

One last thing when it comes to independents: Their Favorability of Congressional Political Parties — Favorability of Congressional political parties –
House Democrats 31% favorable/58% unfavorable
House republicans 29% favorable/61% unfavorable
Senate Democrats 28% favorable/59% unfavorable
Senate Republicans 29% favorable/60% unfavorable

It seems independents hold Biden in very high regards, so far anyway. But when it comes to congressional parties, it’s a pox on both of them. If you want to know how independents still view Trump, he’s at 38% favorable/56% unfavorable compared to Biden’s 54% favorable/ 44% unfavorable.

It's high past time that we start electing Americans to congress and the presidency who put America first instead of their political party. For way too long we have been electing Republicans and Democrats who happen to be Americans instead of Americans who happen to be Republicans and Democrats.